Water Tank Leak

[Flip66]

1989 GB 36 Classic twin with what I believe are 2 original 70 gallon aluminum fresh water tanks. Starboard tank just sprung a leak presumably from the bottom. (Valve closed and all the water drained into the bilge.) Removal of the tank virtually impossible unless you go through the transom (ugh!). Considering opening up access from the top of the tank and either resurfacing inside with epoxy, or putting in a bladder. Anybody have any experience along these lines? Thanks.

 

[AdmiralS]

Friend is having a similar issue.

His trials and tribulations are located here-

https://www.trawlerforum.com/forums/s15/grand-banks-europa-water-tank-alert-57883.html

 

[Bendit]

It is possible that the leak is from a weld in the tank. Often tanks have welds where the end panels are fitted. I have stopped a small leak by peening over the weld with a ball-peen hammer. For a bigger leak, I've used epoxy putty. These were in a 40 year old aluminum fuel tank, which doesn't leak anymore - until the next time.

 

[cks]

Ahoy Admiral S!
Flip 66: I’m the guy AdmiralS is referring to.

I feel your pain.

if you can see the tank on a classic 36 you may be able to start cutting it out in pieces and fitting multiple new tanks in that space. The good news for you is that aluminum can be easily cut apart. You may have to stack tanks and connect them through pipe.
You may be able to pour something into the aluminum tank to seal the pinholes.

If you can get to one side of the tank you may be able to cut a hole into the tank to inspect. If you can cut a hole open and identify where the leak is coming from, provided it’s only one pinhole, you may be able to seal it with either JB water weld from the inside. (careful, it’s only malleable for about five minutes ) or A better product to use would be Belzona pn 1111. ( workable for about 20 minutes)

I haven’t been so lucky.

Good luck.